Cartridge valves for faucets or the like that have plastic and/or ceramic components are well known. See e.g., U.S. Pat. Nos. 3,831,621; and 4,821,765. Production of such valves with mostly metal valve components is time consuming and expensive. Thus, some of these valves incorporate valve components made of a plastic material. This has involved a trade-off, though, because plastic valve components are often more susceptible to breakage and wear.
One cartridge valve that incorporates both metal and plastic components is shown in U.S. Pat. No. 3,780,758. There, a metal stem has a radially extended integral arm, and a plastic valve housing has a pair of spaced abutments. Rotational movement of the valve stem is halted when the metal arm encounters the plastic abutments. This design has several drawbacks. For instance, frequent interaction of the metal component with the generally less rigid plastic component may wear the plastic piece and lead to inexact operation of the valve. Also, if the rotational forces applied to the plastic component become too great, the plastic component may break.
It can therefore be seen that a need exists for an improved cartridge valve that does not generally translate rotational forces between metal and plastic components.